The primary objective of the study is to test efficacy of several drugs in the long-term therapy of coronary heart disease in men ages 30 through 64 with proven previous myocardial infarction. The study has the additional purpose of evaluating the relationship between drug effects on serum cholesterol levels and on morbidity- mortality rates. There will be simultaneous long-term observation of randomly selected patients on placebo treatment. Numerous parameters of experience will be gained in the execution of such long-term collaborative clinical trials. The duration of the program is insufficient at this time to make any definite statements regarding the primary and secondary objectives. Aspirin, a platelet aggregation inhibitor, has recently been added as a study drug to assess its value in prevention of thrombotic coronary artery disease.